TABLE CONTENTS

CHAPTER ONE

Introduction

Retaining walls

Cantilever rw

Rankin theory

Forces on cantilever rw

Counterfort  rw

Forces on counterfort rw

The gravity rw

Forces on gravity rw

CHAPTER TWO

Stability of retaining wall

Soil properties of rws

Drainage in rw

Allowable bearing capacity

CHAPTER THREE

Procedure for the design of rw

Analysis example

Formwork in retaining walls

CHAPTER FOUR

Design Of Cantilever R.W

INTRODUCTION

Retaining walls are structures used  in providing stability for earth or materials where conditions dis allow the materials from summing its nature al slope or stability

There are many factors affecting or militating against the stability of retaining walls. These includes the level of water table behind the wall, size of the base of the wall and nature of the soil retained

Under these effects of he nature of soil,. we have the angle of internal content between the particles, the cohesion which is the bodily contact or binding of the soil particles and the unit weight of the soil . (density)

It is these different parameters that  have been considered individually with different values of height in this study.

NOTATION USED IN THIS PROJECT

1.         Angle of internal friction of soil                                 O

2.         Unit weight of sol                                                       -&

3.         Sat unit wt                                                      -           &sat

4.         sauntered unit wt                                                        - &sub

5.         Overturning moment                           -           Mo

6.         Base width of container wall              -           B

7.         Overall height of wall                                     -           H

8.         Effective height of wall                                  -           He

9.         Height of stem                                                -           h

10.       Effective depth                                               -           d

11.       Overall depth                                      -           d

12.       Weight stem                                                    -           we

13-       Weight soil                                                      -           ws

14.       Surcharge                                                        -           S

15.       Active pressure on wall                                   -           Pa

16.       Passive pressure on wall                                  -           Pp

17.       Breadth for design      -          

18.       Sum of vertical weight                        -           Ew

19.       Point of application of the resultant   X

20.       Eccentricity                                         -           e

21.       Sum of moments                                 -           Em

22.       Characteristic strength steel    -           fy

23.       “          “          ‘           concrete           -           fcn

24.       Lever are factor                                   -           z

25.       Lever are                                                         Z

26.       Ultimate shear stress               -           Vc

27.       Shear force                                          -           V

28.       Shear stress.                                        -           v

CHAPTER ONE

INTRODUCTION

            A clear environment promotes health and esthetics living man has consistency struggled throughout the ages to keep his environment clean. Generally the task of maintaining a heating environment through good sanitary disposal or waste has a become increasing difficult in west Africa and  most developing countries of the world. This is due to such factors as population explanation rapid urbanization, industrialization increased use prepared (package products, changing lifestyle towards out door recreation etc (WAHEB) 1999. a close study of solid waste management has clearly shown that these factors have generated corresponding problems such as  blocked gutters and drainage channels, traffic congestions. overcrowdings, over flooding air pollution and even ineffective refuse management, poor refuse management in out cities has been as associated with other  problems  such as sporadic fireboat breaks, spread of  diseases and distortion of aesthetic value of our environment (Lucas and Giles1990).

            Varies types waste are generated in Enugu, namely solid waste, liquid waste (sewage ad industrial waste (chemical fluent).

            This study is concerned with solid waste which comprises refuse from homes offices and market places. Enugu from its statue as the state capital ,has now become an international commercial center with the recent development in the state (ie the new international center which attracts larger influx of residents and tourists.

            Various attempts have been put in place by the state and local government in the past to enforce refuse management scheme. These effort failed because of poor implementation of these lifting policies the problem of refuse management has assumed a social problem in Enugu, today especially as the Enugu state environment sanitation agency (ENSEPA) appears in capable of handling the task and members of the public appear ignorant and  not ready to co-operate with the authority in keeping Enugu clean like in other cities in Nigeria, the problems of refuse management in Enugu metropolis have defied realistic refuse management solution. This poses gave concern to well meaning citizen of the state

1.2 STATEMENTS OF PROBLEMS

            The one- time held historical and cultural reputation the Enugu city was the cleanest city in Nigeria is fast fading away. in its place great Pyramids of  refuse are found at every junction and street corner begging for removal despite of public out cry, public enlightenment programmes on personal hygiene and environmental health. The refuse heaps blocks the gutters and drain, obstruct traffic flow,, pollute the air encourage instead and trident breeding and the spread of  disease.

            The National sanitation exercise which was introduce  by the head of state General Mohammed Buhari (1984) had then help to check indiscrimate differing of refuse along the streets, but today the story is different since the assumption of chief Olusugn Obasnjo as the president of Nigeria he put an end to it.

            Even with the  introduction of monthly environmental sanitation any the state government it is still unable to meet the standard.

            Refuse was formally collected from house  to house and transferred into a open van. but today the ones that are  still use are put in smaller vehicles and not properly covered, as the vehicle moves on almost all of it spill on the street.

            In view of all the above problem of refuse manager in Enugu metropolis, appear enormous with the local government inadequately positive to tackle it.

            It is the focus of this research project to come up with findings and possible solution to the problem  refuse management in Enugu metropolis.

1.3              OBJECTIVE OF STUDY

The general objective of this study is to critically examine the refuse management problems in Engu metropolis in terms of patterns, storage and final disposal with a view to findings solution to Len.

The specific objectives, however include

1.                  To identify the various methods of refuse management applied in Enugu metropolis

2.                  To asses the effectiveness or adequacy of the existing system of refuse management in Enugu metropolis

3.                  To  identify eh specific problems associated with refuse management

1.4              SIGNIFICANCE OF THE STUDY

The study is significant to the extent that the findings will ascertain the problems arising from effective and inadequate refuse management  and its implication on public health, the study is also important as it findings will beneficial to the state and local government public health sector in their planning of refuse management programs.

1.5              DEFINITION OF TERMS

For purpose of under standing of this study definition of certain terms as are applicable to this study will be advance.

1.                  REFUSE: These consists of heterogeneous mass of deposited waste particle from the house hold, office, market places etc as well as homogenous accumulation of agricultural industrial and mineral waste. it therefore include all participle and non-particle solid waste with the exception of bar waste (exceeta) (Wahab 1991).

2.                  MANAGEMENT: As a process by which responsible persons in an organization (managers or executives at all  levels of management) combine resources (men. Money machinery materials and minute ie time) in achieving a given objectives goals or ends.
(ANN, 1 OGBo andTim Adibe) 2006.

3.                  REFUSE MANAGEMENT: The process of storage collection/transportation and final disposal of solid waste including the after or care of the  disposed site.

4.                  SOLID WASTE: solid waste is refuse which refers to the useless, unwanted or ill discarded materials that arises from mans daily activities, it is required to be disposed the of according to public health laws so that it does not constitute misname to public heath (WAHEB 991)

5.                  Strategies: Is a plan for dealing with uncertain future circumstances (Tim Adibe 2006)

6.                  Prospective: Hopes and expectation for success according to concise oxford dictionary, prospects in relation to this  are the hopes and expectations that refuse management will become successful or unsuccessful given the existing efforts and attempts to solve the problems (Oluwande 1983)

7.                  PROBLEMS: This refers to doubtful or difficult matter requiring a solution. Something hard to understand or accomplish or difficult to deal with (cornice oxford dictionary)

8.                  ROLL-ON-ROLL OFF: Large refuse reacceptances meant to collect refuse from houses and markets at flash sites or communal dumping site. for diseavacuation or rolling on to final disposal site.

This material content is developed to serve as a GUIDE for students to conduct academic research